The present invention relates to vehicle-to-vehicle (V2V) communications systems, and, more particularly, to message relaying using road side units (RSUs) in such systems.
In V2V communications systems that conform to the IEEE 802.11p standard, vehicles transmit basic safety messages (BSMs) to inform other vehicles of their current location, heading, and speed in order to avoid accidents. RSUs are used in V2V communication systems to relay messages between vehicles that do not have a direct line-of-sight (LOS) between them. Such RSUs are provisioned with two omnidirectional (omni) antennas that are located as far apart as possible in order to enable reception diversity at the RSU. Such omni-antennas are separated by a distance equal to multiples of the signal wavelength used to transmit the messages. For systems conforming to the IEEE 802.11p standard, the signal wavelength is in the range of about 5.06 cm to about 5.12 cm, so the two antennas are typically tens of cm apart in a conventional RSU.
It would be advantageous to have an efficient circuit to transmit and decode BSMs transmitted by RSUs.